scholarly journals COVID-19 transmission in educational institutions August to December 2020 in Germany: a study of index cases and close contact cohorts

2021 ◽  
Author(s):  
Anja Schoeps ◽  
Dietmar Hoffmann ◽  
Claudia Tamm ◽  
Bianca Vollmer ◽  
Sabine Haag ◽  
...  
Keyword(s):  
High Risk ◽  
Day Care ◽  
Index Case ◽  
Incidence Rates ◽  
Transmission Risk ◽  
Educational Institutions ◽  
School Closures ◽  
Preventative Measures ◽  
Day Care Centres ◽  
Index Cases

AbstractBackgroundThe lack of precise estimates on transmission risk hampers rational decisions on closure of educational institutions during the COVID-19 pandemic.MethodsSecondary attack rates (SARs) for schools and day-care centres were calculated using data from state-wide mandatory notification of SARS-CoV-2 index cases in educational institutions and information on routine contact tracing and PCR-testing.FindingsFrom August to December 2020, every sixth of overall 784 independent index cases caused a transmission in educational institutions (risk 0·17, 95% CI 0·14–0·19). In a subgroup, monitoring of 14,594 institutional high-risk contacts (89% PCR-tested) of 441 index cases revealed 196 secondary cases (SAR 1·34%, 1·16–1·54). Transmission was more likely from teachers than from students/children (incidence risk ratio [IRR] 3·17, 1·79–5·59), and from index cases in day-care centres (IRR 3·23, 1·76–5·91) than from those in secondary schools. In 748 index cases, teachers caused four times more secondary cases than children (1·08 vs. 0·25 secondary cases per index, IRR 4·39, 2·67–7·21). This difference was mainly due to a large number of teacher-to-teacher transmissions in day-care centres (mean number of secondary cases 0.66) and a very low number of student/child-to-teacher transmissions in schools (mean number of secondary cases 0.004).InterpretationIn educational institutions, the risk of infection for contacts to a confirmed COVID-19 case is one percent, but varies depending on type of institution and index case. Hygiene measures and vaccination targeting the day-care setting and teacher-to-teacher transmission are priorities in reducing the burden of infection and may promote educational justice during the pandemic.FundingNo particular funding was received for this study.Research in contextEvidence before this studyWe searched PubMed on Jan 27, 2021, without any language restrictions for all articles in which the title or abstract contained the search terms “COVID 19” or “corona”, and “school”, “education*”, or “daycare”, and “transmission”, and “risk”, “attack rate”, or “SAR”, and screened 175 results for original research or reviews on COVID-19 transmission risk in the educational setting. Following a similar strategy, we also searched Google Scholar, SSRN, medRxiv, and the reference lists of identified literature. We found five cohort studies on transmission risk looking at overall 171 index cases and their 6,910 contact persons in Australian, Italian, Irish, Singaporean, and German schools and reporting attack rates between 0% and 3% percent. These five studies were conducted before October 2020 and thus looked at COVID-19 transmission risk in schools before the second wave in Europe.A number of modelling studies from the first wave of COVID-19 provide inconclusive guidance to policy makers. While two publications, one from several countries and one from Switzerland, concluded that school closures contributed markedly to the reduction of SARS-CoV-2 transmission and individual mobility, two other studies, one using cross-country data and one from Japan rated school closures among the least effective measures to reduce COVID-19 incidence rates.Added value of this studyBased on a large data set that emerged from the current public health practice in Germany, which incorporates routine PCR-testing during active follow-up of asymptomatic high-risk contacts to index cases, this study provides a precise estimate of the true underlying SARS-CoV-2 transmission risk in schools and day-care centres. Its analysis also allows for a meaningful examination of differences in the risk of transmission with respect to the characteristics of the index case. We found that the individual risk of acquiring SARS-CoV-2 among high-risk contacts in the educational setting is 1.3%, but that this risk rises to 3.2% when the index case is a teacher and to 2.5% when the index case occurs in a day-care centre. Furthermore, we could show that, on average, teacher index cases produced about four times as many secondary cases as student/child index cases. Despite the relatively small proportion of teachers among index cases (20%), our study of transmission pathways revealed that the majority of all secondary cases (54%), and the overwhelming majority of secondary cases in teachers (78%) were caused by teacher index cases. Of note, most cases of teacher-to-teacher transmission (85%) occurred in day-care centres.Implications of all the available evidenceIn this setting, where preventative measures are in place and COVID-19 incidence rates were rising sharply in the population, we found a low and stable transmission risk in educational institutions over time, which provides evidence for the effectiveness of current preventative measures to control the spread of COVID-19 in schools. The identification of a substantial teacher-to-teacher transmission risk in day-care, but a clearly mitigated child/student–to-teacher transmission risk in schools, indicates the need to shift the focus to hygiene among day-care teachers, including infection prevention during staff-meetings and in break rooms. These findings also strongly support the re-prioritization of vaccination against SARS-CoV-2 to educational staff in day-care.

scholarly journals Surveillance of SARS-CoV-2 transmission in educational institutions, August to December 2020, Germany

2021 ◽  
Vol 149 ◽  
Author(s):  
Anja Schoeps ◽  
Dietmar Hoffmann ◽  
Claudia Tamm ◽  
Bianca Vollmer ◽  
Sabine Haag ◽  
...  
Keyword(s):  
High Risk ◽  
Day Care ◽  
Index Case ◽  
Transmission Risk ◽  
Contact Tracing ◽  
Educational Institutions ◽  
Individual Level ◽  
Mandatory Notification ◽  
Day Care Centres ◽  
Index Cases

Abstract This study aims at providing estimates on the transmission risk of SARS-CoV-2 in schools and day-care centres. We calculated secondary attack rates (SARs) using individual-level data from state-wide mandatory notification of index cases in educational institutions, followed by contact tracing and PCR-testing of high-risk contacts. From August to December 2020, every sixth of overall 784 independent index cases was associated with secondary cases in educational institutions. Monitoring of 14 594 institutional high-risk contacts (89% PCR-tested) of 441 index cases during quarantine revealed 196 secondary cases (SAR 1.34%, 0.99–1.78). SARS-CoV-2 infection among high-risk contacts was more likely around teacher-indexes compared to student-/child-indexes (incidence rate ratio (IRR) 3.17, 1.79–5.59), and in day-care centres compared to secondary schools (IRR 3.23, 1.76–5.91), mainly due to clusters around teacher-indexes in day-care containing a higher mean number of secondary cases per index case (142/113 = 1.26) than clusters around student-indexes in schools (82/474 = 0.17). In 2020, SARS-CoV-2 transmission risk in educational settings was low overall, but varied strongly between setting and role of the index case, indicating the chance for targeted intervention. Surveillance of SARS-CoV-2 transmission in educational institutions can powerfully inform public health policy and improve educational justice during the pandemic.

scholarly journals Prevalence and risk factors for in-school transmission of SARS-CoV-2 in Massachusetts K-12 public schools, 2020-2021

2021 ◽  
Author(s):  
Sandra B Nelson ◽  
Caitlin Dugdale ◽  
Alyssa Bilinski ◽  
Duru Cosar ◽  
Nira L Pollock ◽  
...  
Keyword(s):  
Public Schools ◽  
Index Case ◽  
Transmission Risk ◽  
Mitigation Measures ◽  
Contact Tracing ◽  
Convenience Sample ◽  
School Based ◽  
Increased Risk ◽  
K 12 ◽  
Index Cases

Introduction The SARS-CoV-2 secondary attack rate (SAR) in schools is low when mitigation measures are adopted, Data on the relative impact of such strategies are limited. We evaluated the SARS-CoV-2 SAR in Massachusetts schools during 2020-21 and factors associated with transmission risk. Methods: In a convenience sample of 25 Massachusetts public K-12 school districts, de-identified information about SARS-CoV-2 cases and their school-based contacts was reported using a standardized contact-tracing tool. Index cases were included if they were in school while infectious. SAR was defined as the proportion of in-school contacts acquiring SARS-CoV-2 infection and designated as possible or probable in-school transmission by school-based teams. We compared exposure-specific SAR using unadjusted risk ratios (RR) with 95% confidence intervals (CI); p-values were calculated using Fishers exact tests. Results Eight districts (70 schools with >33,000 enrolled students) participated. There were 435 index cases and 1,771 school-based contacts (Table 1). Most contacts (1327/1771 [75%]) underwent SARS-CoV-2 testing and 39/1327 (2.9%) contacts tested positive. Of 39 positive contacts, 10 (25.6%) had clear out-of-school exposures and were deemed not in-school transmissions, so were excluded from further calculations. Twenty-nine (74.4%) contacts were deemed possible or probable in-school transmissions, resulting in an in-school SAR of 2.2%. Of the 29 in-school transmissions, 6 (20.7%) were staff-to-staff, 7 (24.1%) were staff-to-student, 3 (10.3%) were student-to-staff, and 13 (44.8%) were student-to-student; 6 (20.7%) occurred from index cases attending work/school while symptomatic. The unadjusted SAR (Table 2) was significantly higher if the index case was a staff member versus a student (RR 2.18, 95% CI 1.06-4.49; p=0.030), if the index case was identified via in-school contact tracing versus via school-based asymptomatic testing (RR 8.44, 95% CI 1.98-36.06; p=0.001), if the exposure occurred at lunch versus elsewhere (RR 5.74, 95% CI 2.11-15.63; p<0.001; all lunch transmissions were staff-to-staff), and if both parties were unmasked versus both masked (RR 6.98, 95% CI 3.09-15.77; p<0.001). For students, SAR did not differ by grade level. Conclusions Secondary attack rates for SARS-CoV-2 were low in public school settings with comprehensive mitigation measures in place before the emergence of the delta variant; lack of masking and staff-to-staff dining were associated with increased risk.

scholarly journals Risk of SARS-CoV-2 Transmission among Air Passengers in China

2021 ◽  
Author(s):  
Maogui Hu ◽  
Jinfeng Wang ◽  
Hui Lin ◽  
Corrine W Ruktanonchai ◽  
Chengdong Xu ◽  
...  
Keyword(s):  
Relative Risk ◽  
Travel Time ◽  
Index Case ◽  
Epidemiological Data ◽  
Transmission Risk ◽  
Upper And Lower Bounds ◽  
Wuhan City ◽  
Upper Limit ◽  
Index Cases ◽  
Close Contacts

Abstract Background Modern transportation plays a key role in the spread of SARS-CoV-2 and new variants. However, little is known about the exact transmission risk of the virus on airplanes. Methods Using the itinerary and epidemiological data of COVID-19 cases and close contacts on domestic airplanes departing from Wuhan city in China before the lockdown on January 23, 2020, we estimated the upper and lower bounds of overall transmission risk of COVID-19 among travellers. Results 175 index cases were identified among 5797 passengers on 177 airplanes. The upper and lower attack rates (ARs) of a seat were 0.60% (34/5622, 95%CI 0.43%-0.84%) and 0.33% (18/5400, 95%CI 0.21%-0.53%), respectively. In the upper- and lower-bound risk estimates, each index case infected 0.19 (SD 0.45) and 0.10 (SD 0.32) cases respectively. The seats immediately adjacent to the index cases had an AR of 9.2% (95%CI 5.7%-14.4%), with a relative risk 27.8 (95%CI 14.4-53.7) compared to other seats in the upper limit estimation. The middle seat had the highest AR (0.7%, 95%CI 0.4%-1.2%). The upper-bound AR increased from 0.7% (95%CI 0.5%-1.0%) to 1.2% (95%CI 0.4%-3.3%) when the co-travel time increased from 2.0 hours to 3.3 hours. Conclusions The ARs among travellers varied by seat distance from the index case and joint travel time, but the variation was not significant between the types of aircraft. The overall risk of SARS-CoV-2 transmission during domestic travel on planes was relatively low. These findings can improve our understanding of COVID-19 spread during travel and inform response efforts in the pandemic.

scholarly journals Transmission of COVID-19 in 282 clusters in Catalonia, Spain: a cohort study

2020 ◽  
Author(s):  
Michael Marks ◽  
Pere Millat-Martinez ◽  
Dan Ouchi ◽  
Chrissy h. Roberts ◽  
Andrea Alemany ◽  
...  
Keyword(s):  
Viral Load ◽  
Quantitative Pcr ◽  
Incubation Time ◽  
Attack Rate ◽  
Index Case ◽  
Transmission Risk ◽  
Dependent Manner ◽  
Symptomatic Disease ◽  
Dose Dependent ◽  
Index Cases

ABSTRACTBackgroundThere remains limited data on what variables affect risk of transmission of SARS-CoV-2 and developing symptomatic Covid-19 and in particular the relationship to viral load (VL). We analysed data from linked index cases and their contacts to explore factors associated with transmission of SARS-CoV-2.MethodsPatients were recruited as part of a randomized control trial, conducted between March to April 2020, that aimed to assess if hydroxychloroquine reduced transmission of SARS-CoV-2. Non-hospitalised Covid-19 cases and their contacts were identified through the local surveillance system. VL, measured by quantitative PCR from a nasopharyngeal swab, was assessed at enrollment, at day 14, and whenever the participant reported Covid-19-like symptoms. Risk of transmission, developing symptomatic disease and incubation dynamics were evaluated using regression analysis.FindingsWe identified 314 cases, 282 of which had at least one contact (753 contacts in total). Ninety (33%) of 282 clusters had at least one transmission event. The secondary attack rate was 16% (125/753), with a variation from 12% to 24% for VL of the index case of <106, and >109 copies/mL, respectively (OR per log10 increase in VL 1.3 95%CI 1.1–1.6). Increased risk of transmission was also associated with household contact (OR 2.7; 1.4–5.06) and age of the contact (OR 1.02 per year; 1.01–1.04). The proportion of PCR positive contacts who developed symptomatic Covid-19 was 40.3% (181/449), with a variation from 25% to 60% for VL of the contact <107, and >109 copies/mL (HR log10 increase in VL 1.12; 95% CI 1.05 – 1.2). Time to onset of symptomatic disease decreased from a median of 7 days (IQR 5–10) for individuals with an initial viral load <107 to 6 days (4–8) and 5 days (3–8) for individuals with an initial viral load of 107–109 and >109, respectively.InterpretationViral load of index cases is a leading driver of SARS-CoV-2 transmission. The risk of symptomatic Covid-19 is strongly associated with viral load of contacts at baseline and shortens the incubation time in a dose-dependent manner.FundingCrowdfunding campaign YoMeCorono (http://www.yomecorono.com/), and Generalitat de Catalunya. Support for laboratory equipment from Foundation Dormeur.Research in contextEvidence before this studyIn September 2020, we searched PubMed database for articles reporting on factors influencing transmission and the risk of developing symptomatic disease. Search terms included “Covid-19”, “SARS-CoV-2”, “transmission”, “incubation time”, and “risk”, with no language restrictions. By 20th September, various authors had reported on retrospective analyses of clusters of index cases and their corresponding contacts, as well as series of patients who developed symptomatic Covid-19 disease after PCR positive result. Besides describing the secondary attack rate, various authors identified risk factors for transmission associated with the place and duration of exposure and the lack of use of personal protective equipment. A single study suggested that symptomatic individuals might be more likely to transmit than asymptomatic cases but we found no clear evidence regarding the influence of viral load of the index case on transmission risk. Similarly, although various retrospective series of patients with positive PCR results had reported incubation times elsewhere, the characteristics of index case and contacts that may influence the risk of developing symptomatic Covid-19 and the time to this event had been barely addressed.Added value of this studyWe analyzed data from a large cluster-randomized clinical trial on post-exposure therapy for Covid-19 that provide new information on SARS-CoV-2 transmission dynamics. Several design components add value to this dataset. Notably, quantitative PCR was available for the index cases to estimate risk of transmission. Furthermore, quantitative PCR was also performed on asymptomatic contacts at the time of enrollment allowing to investigate the dynamics of symptomatic disease onset among them. We found that the viral load of the index case was the leading determinant of the risk of SARS-CoV-2 PCR positivity among contacts. Among contacts who were SARS-CoV-2 PCR positive at baseline, viral load significantly influenced the risk of developing the symptomatic disease in a dose-dependent manner. This influence also became apparent in the incubation time, which shortened with increasing baseline viral loads.Implication of all the available evidenceOur results provide important insights into the knowledge regarding the risk of SARS-CoV-2 transmission and Covid-19 development. The fact that the transmission risk is primarily driven by the viral load of index cases, more than other factors such as their symptoms or age, suggests that all cases should be considered potential transmitters irrespective of their presentation and encourages assessing viral load in cases with a larger number of close contacts. Similarly, our results regarding the risk and expected time to developing symptomatic Covid-19 encourage risk stratification of newly diagnosed SARS-CoV-2 infections based on the initial viral load.

scholarly journals Household SARS-CoV-2 transmission and children: a network prospective study

2021 ◽  
Author(s):  
Antoni Soriano-Arandes ◽  
Anna Gatell ◽  
Pepe Serrano ◽  
Mireia Biosca ◽  
Ferran Campillo ◽  
...  
Keyword(s):  
Risk Factors ◽  
Index Case ◽  
Viral Transmission ◽  
Transmission Risk ◽  
School Interventions ◽  
Household Transmission ◽  
Household Members ◽  
School Period ◽  
Index Cases

Abstract Background The role of children in household transmission of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) remains uncertain. Here, we describe the epidemiological and clinical characteristics of children with COVID-19 in Catalonia (Spain) and investigate the dynamics of household transmission. Methods Prospective, observational, multicenter study performed during summer and school periods (1 July-31 October, 2020), in which epidemiological and clinical features, and viral transmission dynamics were analyzed in COVID-19 patients &lt;16 years. A pediatric index case was established when a child was the first individual infected within a household. Secondary cases were defined when another household member tested positive for SARS-CoV-2 before the child. The secondary attack rate (SAR) was calculated, and logistic regression was used to assess associations between transmission risk factors and SARS-CoV-2 infections. Results The study included 1040 COVID-19 patients &lt;16 years. Almost half (47.2%) were asymptomatic, 10.8% had comorbidities, and 2.6% required hospitalization. No deaths were reported. Viral transmission was common among household members (62.3%). More than 70% (756/1040) of pediatric cases were secondary to an adult, whereas 7.7% (80/1040) were index cases. The SAR was significantly lower in households with COVID-19 pediatric index cases during the school period relative to summer (p=0.02), and when compared to adults (p=0.006). No individual or environmental risk factors associated with the SAR were identified. Conclusions Children are unlikely to cause household COVID-19 clusters or be major drivers of the pandemic even if attending school. Interventions aimed at children are expected to have a small impact on reducing SARS-CoV-2 transmission.

scholarly journals 30 year experience of index case identification and outcomes of cascade testing in high-risk breast and colorectal cancer predisposition genes

2021 ◽  
Author(s):  
Emma R. Woodward ◽  
Kate Green ◽  
George J. Burghel ◽  
Michael Bulman ◽  
Tara Clancy ◽  
...  
Keyword(s):  
High Risk ◽  
Early Detection ◽  
Cancer Prevention ◽  
Index Case ◽  
Cancer Predisposition ◽  
Index Test ◽  
Cascade Testing ◽  
Index Tests ◽  
High Risk Breast ◽  
Index Cases

AbstractIt is 30 years since the first diagnostic cancer predisposition gene (CPG) test in the Manchester Centre for Genomic Medicine (MCGM), providing opportunities for cancer prevention, early detection and targeted treatments in index cases and at-risk family members. Here, we present time trends (1990–2020) of identification of index cases with a germline CPG variant and numbers of subsequent cascade tests, for 15 high-risk breast and gastro-intestinal tract cancer-associated CPGs: BRCA1, BRCA2, PALB2, PTEN, TP53, APC, BMPR1a, CDH1, MLH1, MSH2, MSH6, PMS2, SMAD4, STK11 and MUTYH. We recorded 2082 positive index case diagnostic screening tests, generating 3216 positive and 3140 negative family cascade (non-index) tests. This is equivalent to an average of 3.05 subsequent cascade tests per positive diagnostic index test, with 1.54 positive and 1.51 negative non-index tests per family. The CPGs with the highest numbers of non-index positive cases identified on cascade testing were BRCA1/2 (n = 1999) and the mismatch repair CPGs associated with Lynch Syndrome (n = 731). These data are important for service provision and health economic assessment of CPG diagnostic testing, in terms of cancer prevention and early detection strategies, and identifying those likely to benefit from targeted treatment strategies.

scholarly journals Household transmission of seasonal coronavirus infections: Results from the Flu Watch cohort study

2020 ◽  
Vol 5 ◽  
pp. 145 ◽  
Author(s):  
Sarah Beale ◽  
Dan Lewer ◽  
Robert W. Aldridge ◽  
Anne M. Johnson ◽  
Maria Zambon ◽  
...  
Keyword(s):  
Cohort Study ◽  
Index Case ◽  
Transmission Risk ◽  
Related Factors ◽  
Household Transmission ◽  
Clinical Onset ◽  
Using Data ◽  
The Uk ◽  
The Impact ◽  
Index Cases

Background: In the context of the current coronavirus disease 2019 (COVID-19) pandemic, understanding household transmission of seasonal coronaviruses may inform pandemic control. We aimed to investigate what proportion of seasonal coronavirus transmission occurred within households, measure the risk of transmission in households, and describe the impact of household-related factors of risk of transmission. Methods: Using data from three winter seasons of the UK Flu Watch cohort study, we measured the proportion of symptomatic infections acquired outside and within the home, the household transmission risk and the household secondary attack risk for PCR-confirmed seasonal coronaviruses. We present transmission risk stratified by demographic features of households. Results: We estimated that the proportion of cases acquired outside the home, weighted by age and region, was 90.7% (95% CI 84.6- 94.5, n=173/195) and within the home was 9.3% (5.5-15.4, 22/195). Following a symptomatic coronavirus index case, 14.9% (9.8 - 22.1, 20/134) of households experienced symptomatic transmission to at least one other household member. Onward transmission risk ranged from 11.90% (4.84-26.36, 5/42) to 19.44% (9.21-36.49, 7/36) by strain. The overall household secondary attack risk for symptomatic cases was 8.00% (5.31-11.88, 22/275), ranging across strains from 5.10 (2.11-11.84, 5/98) to 10.14 (4.82- 20.11, 7/69). Median clinical onset serial interval was 7 days (IQR= 6-9.5). Households including older adults, 3+ children, current smokers, contacts with chronic health conditions, and those in relatively deprived areas had the highest transmission risks. Child index cases and male index cases demonstrated the highest transmission risks. Conclusion: Most seasonal coronaviruses appear to be acquired outside the household, with relatively modest risk of onward transmission within households. Transmission risk following an index case appears to vary by demographic household features, with potential overlap between those demonstrating the highest point estimates for seasonal coronavirus transmission risk and COVID-19 susceptibility and poor illness outcomes.

scholarly journals Early school closures can reduce the first-wave of the COVID-19 pandemic development

2020 ◽  
Author(s):  
Monika Klimek-Tulwin ◽  
Tytus Tulwin
Keyword(s):  
Incidence Rate ◽  
World Economy ◽  
Incidence Rates ◽  
Educational Institutions ◽  
Global Public Health ◽  
Educational Facilities ◽  
School Closures ◽  
Early School ◽  
The World ◽  
Early Closure

Abstract Aim The COVID-19 pandemic presents serious threats to global public health and the world economy. Therefore, the rapid escalation of the number of cases has led to national government and global interventions. This study aimed to assess the effect of school closures on the COVID-19 pandemic and epidemic trajectories in selected countries. Subject and methods Information on the number of cases and population in each country were taken from official government reports. Dates of educational institutions closure were taken from the UNESCO database. Statistical analyses were performed using Statistica. We summarized the data graphically and descriptively. Results Most of the European countries closed schools in the period of 11–20 of March 2020. However, there was a big difference in the phase of the epidemic on the day of closure. The data indicate that there was a strong correlation between the day of educational facilities closure and the incidence rate in the following days (16th, 30th, and 60th days since the 100th confirmed case in each country). Early closure of schools in analyzed countries is statistically significantly correlated with lower incidence rates further on during the different phases of the epidemic. Thereby closure of schools with delay is statistically significantly correlated with a higher incidence rate in the following days. Conclusion The available data suggest that school closures can potentially reduce transmission during the pandemic, although more research is needed on the effectiveness of these practices.

scholarly journals Risk of Secondary Household Transmission of COVID-19 from Health Care Workers in a Hospital in Spain

Epidemiologia ◽  
2021 ◽  
Vol 3 (1) ◽  
pp. 1-10
Author(s):  
Miren Remón-Berrade ◽  
Sara Guillen-Aguinaga ◽  
Isabel Sarrate-Adot ◽  
Maria Pilar Garcia-Garcia ◽  
Maria del Carmen Lerga-Berruezo ◽  
...  
Keyword(s):  
Risk Factors ◽  
Health Care ◽  
Health Care Workers ◽  
Attack Rate ◽  
Index Case ◽  
Acute Infection ◽  
Transmission Risk ◽  
Household Contacts ◽  
Care Workers ◽  
Index Cases

Background: Hospital health care workers are at high risk of developing COVID-19 and transmitting the disease to their family upon returning home; the aim here is to estimate the secondary attack rate of COVID-19 in household contacts of health care workers and their transmission risk factors. Material and Methods: COVID-19 cases in the health care workers of an academic hospital in Pamplona, Spain, from 2 March to 26 May 2020, were followed up. The secondary attack rate (SAR) was estimated from cases in household contacts of index cases and their risk factors by Poisson regression. Results: 89 index cases were studied from 99 notified cases in health care workers (89.0%), excluding secondary cases or those who lived alone. Forty-six secondary cases confirmed by the laboratory were found among 326 household contacts, a secondary attack rate of 14.11% (95% CI 10.75–18.31), and 33 household contacts with acute infection symptoms without microbiologic confirmation 10.12% (95% CI 7.30–13.87). Considering all the cases, the secondary attack rate was 27.3 (95% CI 22.75–32.38). Risk factors were the gender and profession of the index case, the number of people living in the household, and the number of persons per bedroom. When the index case health worker used a single room, it had a protective effect, with an incidence rate ratio (IRR) of 0.493 (95% CI 0.246–0.985); Conclusions: The secondary attack rate found among household contacts of health care workers is high. The preventive isolation of health care workers in individual rooms in their house may reduce the transmission in their families.

Differentiation of endemic areas by incidence rates of tick-borne infectious diseases as the basis for choosing prevention strategy and tactics

2019 ◽  
pp. 56-61
Author(s):  
N.V. Rudakov ◽  
N.A. Penyevskaya ◽  
D.A. Saveliev ◽  
S.A. Rudakova ◽  
C.V. Shtrek ◽  
...  
Keyword(s):  
High Risk ◽  
Infectious Diseases ◽  
Population Based ◽  
Preventive Therapy ◽  
Incidence Rates ◽  
Prevention Strategy ◽  
Individual Risk ◽  
The Individual ◽  
Integral Assessment ◽  
Very High

Research objective. Differentiation of natural focal areas of Western Siberia by integral incidence rates of tick-borne infectious diseases for determination of the strategy and tactics of their comprehensive prevention. Materials and methods. A retrospective analysis of official statistics for the period 2002-2018 for eight sub-federal units in the context of administrative territories was carried out. The criteria of differentiation were determined by means of three evaluation scales, including long-term mean rates of tick-borne encephalitis, tick-borne borreliosis, and Siberian tick-borne typhus. As a scale gradation tool, we used the number of sample elements between the confidence boundaries of the median. The integral assessment was carried out by the sum of points corresponding to the incidence rates for each of the analyzed infections. Results. The areas of low, medium, above average, high and very high risk of tick-borne infectious diseases were determined. Recommendations on the choice of prevention strategy and tactics were given. In areas of very high and high incidence rates, a combination of population-based and individual prevention strategies is preferable while in other areas a combination of high-risk and individual strategies is recommended. Discussion. Epidemiologic zoning should be the basis of a risk-based approach to determining optimal volumes and directions of preventive measures against natural focal infections. It is necessary to improve the means and methods of determining the individual risk of getting infected and developing tick-borne infectious diseases in case of bites, in view of mixed infection of vectors, as well as methods of post-exposure disease prevention (preventive therapy).

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